We have switched!! This beats all other sippy cups by miles! Extremely durable- can withstand high velocity impact on wood floor, concrete, and most other hard surfaces. Easy to clean- only 3 parts! Take it apart and toss in dishwasher and voila. Plastic spout is durable- withstands strong force of teething toddlers, (puppies too!).
Only drawbacks- - I would like to buy just the top screw on part (just in case a puppy does destroy it, or a teething toddler) - and the plastic insert CAN pop out inside the cup if it does meet a hard surface with high velocity. (I just fish it out and pop it back in)
With that said, I still recommend this cup. It holds more than most sippy cups and is pretty cool looking as well. Other sippies have come and gone in this house but the 4 Nalgene we have are still standing and intact- and look brand new too!